xref: /dflybsd-src/sys/kern/kern_proc.c (revision 127a3eb4035f914ee311e89500f4d77abda51b3f)
1 /*
2  * (MPSAFE)
3  *
4  * Copyright (c) 1982, 1986, 1989, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)kern_proc.c	8.7 (Berkeley) 2/14/95
36  * $FreeBSD: src/sys/kern/kern_proc.c,v 1.63.2.9 2003/05/08 07:47:16 kbyanc Exp $
37  * $DragonFly: src/sys/kern/kern_proc.c,v 1.45 2008/06/12 23:25:02 dillon Exp $
38  */
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/sysctl.h>
44 #include <sys/malloc.h>
45 #include <sys/proc.h>
46 #include <sys/jail.h>
47 #include <sys/filedesc.h>
48 #include <sys/tty.h>
49 #include <sys/dsched.h>
50 #include <sys/signalvar.h>
51 #include <sys/spinlock.h>
52 #include <vm/vm.h>
53 #include <sys/lock.h>
54 #include <vm/pmap.h>
55 #include <vm/vm_map.h>
56 #include <sys/user.h>
57 #include <machine/smp.h>
58 
59 #include <sys/refcount.h>
60 #include <sys/spinlock2.h>
61 #include <sys/mplock2.h>
62 
63 static MALLOC_DEFINE(M_PGRP, "pgrp", "process group header");
64 MALLOC_DEFINE(M_SESSION, "session", "session header");
65 MALLOC_DEFINE(M_PROC, "proc", "Proc structures");
66 MALLOC_DEFINE(M_LWP, "lwp", "lwp structures");
67 MALLOC_DEFINE(M_SUBPROC, "subproc", "Proc sub-structures");
68 
69 int ps_showallprocs = 1;
70 static int ps_showallthreads = 1;
71 SYSCTL_INT(_security, OID_AUTO, ps_showallprocs, CTLFLAG_RW,
72     &ps_showallprocs, 0,
73     "Unprivileged processes can see proccesses with different UID/GID");
74 SYSCTL_INT(_security, OID_AUTO, ps_showallthreads, CTLFLAG_RW,
75     &ps_showallthreads, 0,
76     "Unprivileged processes can see kernel threads");
77 
78 static void pgdelete(struct pgrp *);
79 static void orphanpg(struct pgrp *pg);
80 static pid_t proc_getnewpid_locked(int random_offset);
81 
82 /*
83  * Other process lists
84  */
85 struct pidhashhead *pidhashtbl;
86 u_long pidhash;
87 struct pgrphashhead *pgrphashtbl;
88 u_long pgrphash;
89 struct proclist allproc;
90 struct proclist zombproc;
91 
92 /*
93  * Random component to nextpid generation.  We mix in a random factor to make
94  * it a little harder to predict.  We sanity check the modulus value to avoid
95  * doing it in critical paths.  Don't let it be too small or we pointlessly
96  * waste randomness entropy, and don't let it be impossibly large.  Using a
97  * modulus that is too big causes a LOT more process table scans and slows
98  * down fork processing as the pidchecked caching is defeated.
99  */
100 static int randompid = 0;
101 
102 /*
103  * No requirements.
104  */
105 static int
106 sysctl_kern_randompid(SYSCTL_HANDLER_ARGS)
107 {
108 	int error, pid;
109 
110 	pid = randompid;
111 	error = sysctl_handle_int(oidp, &pid, 0, req);
112 	if (error || !req->newptr)
113 		return (error);
114 	if (pid < 0 || pid > PID_MAX - 100)     /* out of range */
115 		pid = PID_MAX - 100;
116 	else if (pid < 2)                       /* NOP */
117 		pid = 0;
118 	else if (pid < 100)                     /* Make it reasonable */
119 		pid = 100;
120 	randompid = pid;
121 	return (error);
122 }
123 
124 SYSCTL_PROC(_kern, OID_AUTO, randompid, CTLTYPE_INT|CTLFLAG_RW,
125 	    0, 0, sysctl_kern_randompid, "I", "Random PID modulus");
126 
127 /*
128  * Initialize global process hashing structures.
129  *
130  * Called from the low level boot code only.
131  */
132 void
133 procinit(void)
134 {
135 	LIST_INIT(&allproc);
136 	LIST_INIT(&zombproc);
137 	lwkt_init();
138 	pidhashtbl = hashinit(maxproc / 4, M_PROC, &pidhash);
139 	pgrphashtbl = hashinit(maxproc / 4, M_PROC, &pgrphash);
140 	uihashinit();
141 }
142 
143 /*
144  * Is p an inferior of the current process?
145  *
146  * No requirements.
147  * The caller must hold proc_token if the caller wishes a stable result.
148  */
149 int
150 inferior(struct proc *p)
151 {
152 	lwkt_gettoken(&proc_token);
153 	while (p != curproc) {
154 		if (p->p_pid == 0) {
155 			lwkt_reltoken(&proc_token);
156 			return (0);
157 		}
158 		p = p->p_pptr;
159 	}
160 	lwkt_reltoken(&proc_token);
161 	return (1);
162 }
163 
164 /*
165  * Locate a process by number.  The returned process will be referenced and
166  * must be released with PRELE().
167  *
168  * No requirements.
169  */
170 struct proc *
171 pfind(pid_t pid)
172 {
173 	struct proc *p;
174 
175 	lwkt_gettoken(&proc_token);
176 	LIST_FOREACH(p, PIDHASH(pid), p_hash) {
177 		if (p->p_pid == pid) {
178 			PHOLD(p);
179 			lwkt_reltoken(&proc_token);
180 			return (p);
181 		}
182 	}
183 	lwkt_reltoken(&proc_token);
184 	return (NULL);
185 }
186 
187 /*
188  * Locate a process by number.  The returned process is NOT referenced.
189  * The caller should hold proc_token if the caller wishes a stable result.
190  *
191  * No requirements.
192  */
193 struct proc *
194 pfindn(pid_t pid)
195 {
196 	struct proc *p;
197 
198 	lwkt_gettoken(&proc_token);
199 	LIST_FOREACH(p, PIDHASH(pid), p_hash) {
200 		if (p->p_pid == pid) {
201 			lwkt_reltoken(&proc_token);
202 			return (p);
203 		}
204 	}
205 	lwkt_reltoken(&proc_token);
206 	return (NULL);
207 }
208 
209 void
210 pgref(struct pgrp *pgrp)
211 {
212 	refcount_acquire(&pgrp->pg_refs);
213 }
214 
215 void
216 pgrel(struct pgrp *pgrp)
217 {
218 	if (refcount_release(&pgrp->pg_refs))
219 		pgdelete(pgrp);
220 }
221 
222 /*
223  * Locate a process group by number.  The returned process group will be
224  * referenced w/pgref() and must be released with pgrel() (or assigned
225  * somewhere if you wish to keep the reference).
226  *
227  * No requirements.
228  */
229 struct pgrp *
230 pgfind(pid_t pgid)
231 {
232 	struct pgrp *pgrp;
233 
234 	lwkt_gettoken(&proc_token);
235 	LIST_FOREACH(pgrp, PGRPHASH(pgid), pg_hash) {
236 		if (pgrp->pg_id == pgid) {
237 			refcount_acquire(&pgrp->pg_refs);
238 			lwkt_reltoken(&proc_token);
239 			return (pgrp);
240 		}
241 	}
242 	lwkt_reltoken(&proc_token);
243 	return (NULL);
244 }
245 
246 /*
247  * Move p to a new or existing process group (and session)
248  *
249  * No requirements.
250  */
251 int
252 enterpgrp(struct proc *p, pid_t pgid, int mksess)
253 {
254 	struct pgrp *pgrp;
255 	struct pgrp *opgrp;
256 	int error;
257 
258 	pgrp = pgfind(pgid);
259 
260 	KASSERT(pgrp == NULL || !mksess,
261 		("enterpgrp: setsid into non-empty pgrp"));
262 	KASSERT(!SESS_LEADER(p),
263 		("enterpgrp: session leader attempted setpgrp"));
264 
265 	if (pgrp == NULL) {
266 		pid_t savepid = p->p_pid;
267 		struct proc *np;
268 		/*
269 		 * new process group
270 		 */
271 		KASSERT(p->p_pid == pgid,
272 			("enterpgrp: new pgrp and pid != pgid"));
273 		if ((np = pfindn(savepid)) == NULL || np != p) {
274 			error = ESRCH;
275 			goto fatal;
276 		}
277 		MALLOC(pgrp, struct pgrp *, sizeof(struct pgrp),
278 		       M_PGRP, M_WAITOK);
279 		if (mksess) {
280 			struct session *sess;
281 
282 			/*
283 			 * new session
284 			 */
285 			MALLOC(sess, struct session *, sizeof(struct session),
286 			       M_SESSION, M_WAITOK);
287 			sess->s_leader = p;
288 			sess->s_sid = p->p_pid;
289 			sess->s_count = 1;
290 			sess->s_ttyvp = NULL;
291 			sess->s_ttyp = NULL;
292 			bcopy(p->p_session->s_login, sess->s_login,
293 			      sizeof(sess->s_login));
294 			p->p_flag &= ~P_CONTROLT;
295 			pgrp->pg_session = sess;
296 			KASSERT(p == curproc,
297 				("enterpgrp: mksession and p != curproc"));
298 		} else {
299 			pgrp->pg_session = p->p_session;
300 			sess_hold(pgrp->pg_session);
301 		}
302 		pgrp->pg_id = pgid;
303 		LIST_INIT(&pgrp->pg_members);
304 		LIST_INSERT_HEAD(PGRPHASH(pgid), pgrp, pg_hash);
305 		pgrp->pg_jobc = 0;
306 		SLIST_INIT(&pgrp->pg_sigiolst);
307 		lwkt_token_init(&pgrp->pg_token, "pgrp_token");
308 		refcount_init(&pgrp->pg_refs, 1);
309 		lockinit(&pgrp->pg_lock, "pgwt", 0, 0);
310 	} else if (pgrp == p->p_pgrp) {
311 		pgrel(pgrp);
312 		goto done;
313 	} /* else pgfind() referenced the pgrp */
314 
315 	/*
316 	 * Adjust eligibility of affected pgrps to participate in job control.
317 	 * Increment eligibility counts before decrementing, otherwise we
318 	 * could reach 0 spuriously during the first call.
319 	 */
320 	lwkt_gettoken(&pgrp->pg_token);
321 	lwkt_gettoken(&p->p_token);
322 	fixjobc(p, pgrp, 1);
323 	fixjobc(p, p->p_pgrp, 0);
324 	while ((opgrp = p->p_pgrp) != NULL) {
325 		opgrp = p->p_pgrp;
326 		lwkt_gettoken(&opgrp->pg_token);
327 		LIST_REMOVE(p, p_pglist);
328 		p->p_pgrp = NULL;
329 		lwkt_reltoken(&opgrp->pg_token);
330 		pgrel(opgrp);
331 	}
332 	p->p_pgrp = pgrp;
333 	LIST_INSERT_HEAD(&pgrp->pg_members, p, p_pglist);
334 	lwkt_reltoken(&p->p_token);
335 	lwkt_reltoken(&pgrp->pg_token);
336 done:
337 	error = 0;
338 fatal:
339 	return (error);
340 }
341 
342 /*
343  * Remove process from process group
344  *
345  * No requirements.
346  */
347 int
348 leavepgrp(struct proc *p)
349 {
350 	struct pgrp *pg = p->p_pgrp;
351 
352 	lwkt_gettoken(&p->p_token);
353 	pg = p->p_pgrp;
354 	if (pg) {
355 		pgref(pg);
356 		lwkt_gettoken(&pg->pg_token);
357 		if (p->p_pgrp == pg) {
358 			p->p_pgrp = NULL;
359 			LIST_REMOVE(p, p_pglist);
360 			pgrel(pg);
361 		}
362 		lwkt_reltoken(&pg->pg_token);
363 		lwkt_reltoken(&p->p_token);	/* avoid chaining on rel */
364 		pgrel(pg);
365 	} else {
366 		lwkt_reltoken(&p->p_token);
367 	}
368 	return (0);
369 }
370 
371 /*
372  * Delete a process group.  Must be called only after the last ref has been
373  * released.
374  */
375 static void
376 pgdelete(struct pgrp *pgrp)
377 {
378 	/*
379 	 * Reset any sigio structures pointing to us as a result of
380 	 * F_SETOWN with our pgid.
381 	 */
382 	funsetownlst(&pgrp->pg_sigiolst);
383 
384 	if (pgrp->pg_session->s_ttyp != NULL &&
385 	    pgrp->pg_session->s_ttyp->t_pgrp == pgrp)
386 		pgrp->pg_session->s_ttyp->t_pgrp = NULL;
387 	LIST_REMOVE(pgrp, pg_hash);
388 	sess_rele(pgrp->pg_session);
389 	kfree(pgrp, M_PGRP);
390 }
391 
392 /*
393  * Adjust the ref count on a session structure.  When the ref count falls to
394  * zero the tty is disassociated from the session and the session structure
395  * is freed.  Note that tty assocation is not itself ref-counted.
396  *
397  * No requirements.
398  */
399 void
400 sess_hold(struct session *sp)
401 {
402 	lwkt_gettoken(&tty_token);
403 	++sp->s_count;
404 	lwkt_reltoken(&tty_token);
405 }
406 
407 /*
408  * No requirements.
409  */
410 void
411 sess_rele(struct session *sp)
412 {
413 	struct tty *tp;
414 
415 	KKASSERT(sp->s_count > 0);
416 	lwkt_gettoken(&tty_token);
417 	if (--sp->s_count == 0) {
418 		if (sp->s_ttyp && sp->s_ttyp->t_session) {
419 #ifdef TTY_DO_FULL_CLOSE
420 			/* FULL CLOSE, see ttyclearsession() */
421 			KKASSERT(sp->s_ttyp->t_session == sp);
422 			sp->s_ttyp->t_session = NULL;
423 #else
424 			/* HALF CLOSE, see ttyclearsession() */
425 			if (sp->s_ttyp->t_session == sp)
426 				sp->s_ttyp->t_session = NULL;
427 #endif
428 		}
429 		if ((tp = sp->s_ttyp) != NULL) {
430 			sp->s_ttyp = NULL;
431 			ttyunhold(tp);
432 		}
433 		kfree(sp, M_SESSION);
434 	}
435 	lwkt_reltoken(&tty_token);
436 }
437 
438 /*
439  * Adjust pgrp jobc counters when specified process changes process group.
440  * We count the number of processes in each process group that "qualify"
441  * the group for terminal job control (those with a parent in a different
442  * process group of the same session).  If that count reaches zero, the
443  * process group becomes orphaned.  Check both the specified process'
444  * process group and that of its children.
445  * entering == 0 => p is leaving specified group.
446  * entering == 1 => p is entering specified group.
447  *
448  * No requirements.
449  */
450 void
451 fixjobc(struct proc *p, struct pgrp *pgrp, int entering)
452 {
453 	struct pgrp *hispgrp;
454 	struct session *mysession;
455 	struct proc *np;
456 
457 	/*
458 	 * Check p's parent to see whether p qualifies its own process
459 	 * group; if so, adjust count for p's process group.
460 	 */
461 	lwkt_gettoken(&p->p_token);	/* p_children scan */
462 	lwkt_gettoken(&pgrp->pg_token);
463 
464 	mysession = pgrp->pg_session;
465 	if ((hispgrp = p->p_pptr->p_pgrp) != pgrp &&
466 	    hispgrp->pg_session == mysession) {
467 		if (entering)
468 			pgrp->pg_jobc++;
469 		else if (--pgrp->pg_jobc == 0)
470 			orphanpg(pgrp);
471 	}
472 
473 	/*
474 	 * Check this process' children to see whether they qualify
475 	 * their process groups; if so, adjust counts for children's
476 	 * process groups.
477 	 */
478 	LIST_FOREACH(np, &p->p_children, p_sibling) {
479 		PHOLD(np);
480 		lwkt_gettoken(&np->p_token);
481 		if ((hispgrp = np->p_pgrp) != pgrp &&
482 		    hispgrp->pg_session == mysession &&
483 		    np->p_stat != SZOMB) {
484 			pgref(hispgrp);
485 			lwkt_gettoken(&hispgrp->pg_token);
486 			if (entering)
487 				hispgrp->pg_jobc++;
488 			else if (--hispgrp->pg_jobc == 0)
489 				orphanpg(hispgrp);
490 			lwkt_reltoken(&hispgrp->pg_token);
491 			pgrel(hispgrp);
492 		}
493 		lwkt_reltoken(&np->p_token);
494 		PRELE(np);
495 	}
496 	KKASSERT(pgrp->pg_refs > 0);
497 	lwkt_reltoken(&pgrp->pg_token);
498 	lwkt_reltoken(&p->p_token);
499 }
500 
501 /*
502  * A process group has become orphaned;
503  * if there are any stopped processes in the group,
504  * hang-up all process in that group.
505  *
506  * The caller must hold pg_token.
507  */
508 static void
509 orphanpg(struct pgrp *pg)
510 {
511 	struct proc *p;
512 
513 	LIST_FOREACH(p, &pg->pg_members, p_pglist) {
514 		if (p->p_stat == SSTOP) {
515 			LIST_FOREACH(p, &pg->pg_members, p_pglist) {
516 				ksignal(p, SIGHUP);
517 				ksignal(p, SIGCONT);
518 			}
519 			return;
520 		}
521 	}
522 }
523 
524 /*
525  * Add a new process to the allproc list and the PID hash.  This
526  * also assigns a pid to the new process.
527  *
528  * No requirements.
529  */
530 void
531 proc_add_allproc(struct proc *p)
532 {
533 	int random_offset;
534 
535 	if ((random_offset = randompid) != 0) {
536 		get_mplock();
537 		random_offset = karc4random() % random_offset;
538 		rel_mplock();
539 	}
540 
541 	lwkt_gettoken(&proc_token);
542 	p->p_pid = proc_getnewpid_locked(random_offset);
543 	LIST_INSERT_HEAD(&allproc, p, p_list);
544 	LIST_INSERT_HEAD(PIDHASH(p->p_pid), p, p_hash);
545 	lwkt_reltoken(&proc_token);
546 }
547 
548 /*
549  * Calculate a new process pid.  This function is integrated into
550  * proc_add_allproc() to guarentee that the new pid is not reused before
551  * the new process can be added to the allproc list.
552  *
553  * The caller must hold proc_token.
554  */
555 static
556 pid_t
557 proc_getnewpid_locked(int random_offset)
558 {
559 	static pid_t nextpid;
560 	static pid_t pidchecked;
561 	struct proc *p;
562 
563 	/*
564 	 * Find an unused process ID.  We remember a range of unused IDs
565 	 * ready to use (from nextpid+1 through pidchecked-1).
566 	 */
567 	nextpid = nextpid + 1 + random_offset;
568 retry:
569 	/*
570 	 * If the process ID prototype has wrapped around,
571 	 * restart somewhat above 0, as the low-numbered procs
572 	 * tend to include daemons that don't exit.
573 	 */
574 	if (nextpid >= PID_MAX) {
575 		nextpid = nextpid % PID_MAX;
576 		if (nextpid < 100)
577 			nextpid += 100;
578 		pidchecked = 0;
579 	}
580 	if (nextpid >= pidchecked) {
581 		int doingzomb = 0;
582 
583 		pidchecked = PID_MAX;
584 		/*
585 		 * Scan the active and zombie procs to check whether this pid
586 		 * is in use.  Remember the lowest pid that's greater
587 		 * than nextpid, so we can avoid checking for a while.
588 		 */
589 		p = LIST_FIRST(&allproc);
590 again:
591 		for (; p != 0; p = LIST_NEXT(p, p_list)) {
592 			while (p->p_pid == nextpid ||
593 			    p->p_pgrp->pg_id == nextpid ||
594 			    p->p_session->s_sid == nextpid) {
595 				nextpid++;
596 				if (nextpid >= pidchecked)
597 					goto retry;
598 			}
599 			if (p->p_pid > nextpid && pidchecked > p->p_pid)
600 				pidchecked = p->p_pid;
601 			if (p->p_pgrp->pg_id > nextpid &&
602 			    pidchecked > p->p_pgrp->pg_id)
603 				pidchecked = p->p_pgrp->pg_id;
604 			if (p->p_session->s_sid > nextpid &&
605 			    pidchecked > p->p_session->s_sid)
606 				pidchecked = p->p_session->s_sid;
607 		}
608 		if (!doingzomb) {
609 			doingzomb = 1;
610 			p = LIST_FIRST(&zombproc);
611 			goto again;
612 		}
613 	}
614 	return(nextpid);
615 }
616 
617 /*
618  * Called from exit1 to remove a process from the allproc
619  * list and move it to the zombie list.
620  *
621  * No requirements.
622  */
623 void
624 proc_move_allproc_zombie(struct proc *p)
625 {
626 	lwkt_gettoken(&proc_token);
627 	while (p->p_lock) {
628 		tsleep(p, 0, "reap1", hz / 10);
629 	}
630 	LIST_REMOVE(p, p_list);
631 	LIST_INSERT_HEAD(&zombproc, p, p_list);
632 	LIST_REMOVE(p, p_hash);
633 	p->p_stat = SZOMB;
634 	lwkt_reltoken(&proc_token);
635 	dsched_exit_proc(p);
636 }
637 
638 /*
639  * This routine is called from kern_wait() and will remove the process
640  * from the zombie list and the sibling list.  This routine will block
641  * if someone has a lock on the proces (p_lock).
642  *
643  * No requirements.
644  */
645 void
646 proc_remove_zombie(struct proc *p)
647 {
648 	lwkt_gettoken(&proc_token);
649 	while (p->p_lock) {
650 		tsleep(p, 0, "reap1", hz / 10);
651 	}
652 	LIST_REMOVE(p, p_list); /* off zombproc */
653 	LIST_REMOVE(p, p_sibling);
654 	lwkt_reltoken(&proc_token);
655 }
656 
657 /*
658  * Scan all processes on the allproc list.  The process is automatically
659  * held for the callback.  A return value of -1 terminates the loop.
660  *
661  * No requirements.
662  * The callback is made with the process held and proc_token held.
663  */
664 void
665 allproc_scan(int (*callback)(struct proc *, void *), void *data)
666 {
667 	struct proc *p;
668 	int r;
669 
670 	lwkt_gettoken(&proc_token);
671 	LIST_FOREACH(p, &allproc, p_list) {
672 		PHOLD(p);
673 		r = callback(p, data);
674 		PRELE(p);
675 		if (r < 0)
676 			break;
677 	}
678 	lwkt_reltoken(&proc_token);
679 }
680 
681 /*
682  * Scan all lwps of processes on the allproc list.  The lwp is automatically
683  * held for the callback.  A return value of -1 terminates the loop.
684  *
685  * No requirements.
686  * The callback is made with the proces and lwp both held, and proc_token held.
687  */
688 void
689 alllwp_scan(int (*callback)(struct lwp *, void *), void *data)
690 {
691 	struct proc *p;
692 	struct lwp *lp;
693 	int r = 0;
694 
695 	lwkt_gettoken(&proc_token);
696 	LIST_FOREACH(p, &allproc, p_list) {
697 		PHOLD(p);
698 		FOREACH_LWP_IN_PROC(lp, p) {
699 			LWPHOLD(lp);
700 			r = callback(lp, data);
701 			LWPRELE(lp);
702 		}
703 		PRELE(p);
704 		if (r < 0)
705 			break;
706 	}
707 	lwkt_reltoken(&proc_token);
708 }
709 
710 /*
711  * Scan all processes on the zombproc list.  The process is automatically
712  * held for the callback.  A return value of -1 terminates the loop.
713  *
714  * No requirements.
715  * The callback is made with the proces held and proc_token held.
716  */
717 void
718 zombproc_scan(int (*callback)(struct proc *, void *), void *data)
719 {
720 	struct proc *p;
721 	int r;
722 
723 	lwkt_gettoken(&proc_token);
724 	LIST_FOREACH(p, &zombproc, p_list) {
725 		PHOLD(p);
726 		r = callback(p, data);
727 		PRELE(p);
728 		if (r < 0)
729 			break;
730 	}
731 	lwkt_reltoken(&proc_token);
732 }
733 
734 #include "opt_ddb.h"
735 #ifdef DDB
736 #include <ddb/ddb.h>
737 
738 /*
739  * Debugging only
740  */
741 DB_SHOW_COMMAND(pgrpdump, pgrpdump)
742 {
743 	struct pgrp *pgrp;
744 	struct proc *p;
745 	int i;
746 
747 	for (i = 0; i <= pgrphash; i++) {
748 		if (!LIST_EMPTY(&pgrphashtbl[i])) {
749 			kprintf("\tindx %d\n", i);
750 			LIST_FOREACH(pgrp, &pgrphashtbl[i], pg_hash) {
751 				kprintf(
752 			"\tpgrp %p, pgid %ld, sess %p, sesscnt %d, mem %p\n",
753 				    (void *)pgrp, (long)pgrp->pg_id,
754 				    (void *)pgrp->pg_session,
755 				    pgrp->pg_session->s_count,
756 				    (void *)LIST_FIRST(&pgrp->pg_members));
757 				LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
758 					kprintf("\t\tpid %ld addr %p pgrp %p\n",
759 					    (long)p->p_pid, (void *)p,
760 					    (void *)p->p_pgrp);
761 				}
762 			}
763 		}
764 	}
765 }
766 #endif /* DDB */
767 
768 /*
769  * Locate a process on the zombie list.  Return a process or NULL.
770  * The returned process will be referenced and the caller must release
771  * it with PRELE().
772  *
773  * No other requirements.
774  */
775 struct proc *
776 zpfind(pid_t pid)
777 {
778 	struct proc *p;
779 
780 	lwkt_gettoken(&proc_token);
781 	LIST_FOREACH(p, &zombproc, p_list) {
782 		if (p->p_pid == pid) {
783 			PHOLD(p);
784 			lwkt_reltoken(&proc_token);
785 			return (p);
786 		}
787 	}
788 	lwkt_reltoken(&proc_token);
789 	return (NULL);
790 }
791 
792 /*
793  * The caller must hold proc_token.
794  */
795 static int
796 sysctl_out_proc(struct proc *p, struct sysctl_req *req, int flags)
797 {
798 	struct kinfo_proc ki;
799 	struct lwp *lp;
800 	int skp = 0, had_output = 0;
801 	int error;
802 
803 	bzero(&ki, sizeof(ki));
804 	fill_kinfo_proc(p, &ki);
805 	if ((flags & KERN_PROC_FLAG_LWP) == 0)
806 		skp = 1;
807 	error = 0;
808 	FOREACH_LWP_IN_PROC(lp, p) {
809 		LWPHOLD(lp);
810 		fill_kinfo_lwp(lp, &ki.kp_lwp);
811 		had_output = 1;
812 		error = SYSCTL_OUT(req, &ki, sizeof(ki));
813 		LWPRELE(lp);
814 		if (error)
815 			break;
816 		if (skp)
817 			break;
818 	}
819 	/* We need to output at least the proc, even if there is no lwp. */
820 	if (had_output == 0) {
821 		error = SYSCTL_OUT(req, &ki, sizeof(ki));
822 	}
823 	return (error);
824 }
825 
826 /*
827  * The caller must hold proc_token.
828  */
829 static int
830 sysctl_out_proc_kthread(struct thread *td, struct sysctl_req *req, int flags)
831 {
832 	struct kinfo_proc ki;
833 	int error;
834 
835 	fill_kinfo_proc_kthread(td, &ki);
836 	error = SYSCTL_OUT(req, &ki, sizeof(ki));
837 	if (error)
838 		return error;
839 	return(0);
840 }
841 
842 /*
843  * No requirements.
844  */
845 static int
846 sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
847 {
848 	int *name = (int*) arg1;
849 	int oid = oidp->oid_number;
850 	u_int namelen = arg2;
851 	struct proc *p;
852 	struct proclist *plist;
853 	struct thread *td;
854 	int doingzomb, flags = 0;
855 	int error = 0;
856 	int n;
857 	int origcpu;
858 	struct ucred *cr1 = curproc->p_ucred;
859 
860 	flags = oid & KERN_PROC_FLAGMASK;
861 	oid &= ~KERN_PROC_FLAGMASK;
862 
863 	if ((oid == KERN_PROC_ALL && namelen != 0) ||
864 	    (oid != KERN_PROC_ALL && namelen != 1))
865 		return (EINVAL);
866 
867 	lwkt_gettoken(&proc_token);
868 	if (oid == KERN_PROC_PID) {
869 		p = pfindn((pid_t)name[0]);
870 		if (p == NULL)
871 			goto post_threads;
872 		if (!PRISON_CHECK(cr1, p->p_ucred))
873 			goto post_threads;
874 		PHOLD(p);
875 		error = sysctl_out_proc(p, req, flags);
876 		PRELE(p);
877 		goto post_threads;
878 	}
879 
880 	if (!req->oldptr) {
881 		/* overestimate by 5 procs */
882 		error = SYSCTL_OUT(req, 0, sizeof (struct kinfo_proc) * 5);
883 		if (error)
884 			goto post_threads;
885 	}
886 	for (doingzomb = 0; doingzomb <= 1; doingzomb++) {
887 		if (doingzomb)
888 			plist = &zombproc;
889 		else
890 			plist = &allproc;
891 		LIST_FOREACH(p, plist, p_list) {
892 			/*
893 			 * Show a user only their processes.
894 			 */
895 			if ((!ps_showallprocs) && p_trespass(cr1, p->p_ucred))
896 				continue;
897 			/*
898 			 * Skip embryonic processes.
899 			 */
900 			if (p->p_stat == SIDL)
901 				continue;
902 			/*
903 			 * TODO - make more efficient (see notes below).
904 			 * do by session.
905 			 */
906 			switch (oid) {
907 			case KERN_PROC_PGRP:
908 				/* could do this by traversing pgrp */
909 				if (p->p_pgrp == NULL ||
910 				    p->p_pgrp->pg_id != (pid_t)name[0])
911 					continue;
912 				break;
913 
914 			case KERN_PROC_TTY:
915 				if ((p->p_flag & P_CONTROLT) == 0 ||
916 				    p->p_session == NULL ||
917 				    p->p_session->s_ttyp == NULL ||
918 				    dev2udev(p->p_session->s_ttyp->t_dev) !=
919 					(udev_t)name[0])
920 					continue;
921 				break;
922 
923 			case KERN_PROC_UID:
924 				if (p->p_ucred == NULL ||
925 				    p->p_ucred->cr_uid != (uid_t)name[0])
926 					continue;
927 				break;
928 
929 			case KERN_PROC_RUID:
930 				if (p->p_ucred == NULL ||
931 				    p->p_ucred->cr_ruid != (uid_t)name[0])
932 					continue;
933 				break;
934 			}
935 
936 			if (!PRISON_CHECK(cr1, p->p_ucred))
937 				continue;
938 			PHOLD(p);
939 			error = sysctl_out_proc(p, req, flags);
940 			PRELE(p);
941 			if (error)
942 				goto post_threads;
943 		}
944 	}
945 
946 	/*
947 	 * Iterate over all active cpus and scan their thread list.  Start
948 	 * with the next logical cpu and end with our original cpu.  We
949 	 * migrate our own thread to each target cpu in order to safely scan
950 	 * its thread list.  In the last loop we migrate back to our original
951 	 * cpu.
952 	 */
953 	origcpu = mycpu->gd_cpuid;
954 	if (!ps_showallthreads || jailed(cr1))
955 		goto post_threads;
956 
957 	for (n = 1; n <= ncpus; ++n) {
958 		globaldata_t rgd;
959 		int nid;
960 
961 		nid = (origcpu + n) % ncpus;
962 		if ((smp_active_mask & CPUMASK(nid)) == 0)
963 			continue;
964 		rgd = globaldata_find(nid);
965 		lwkt_setcpu_self(rgd);
966 
967 		TAILQ_FOREACH(td, &mycpu->gd_tdallq, td_allq) {
968 			if (td->td_proc)
969 				continue;
970 			switch (oid) {
971 			case KERN_PROC_PGRP:
972 			case KERN_PROC_TTY:
973 			case KERN_PROC_UID:
974 			case KERN_PROC_RUID:
975 				continue;
976 			default:
977 				break;
978 			}
979 			lwkt_hold(td);
980 			error = sysctl_out_proc_kthread(td, req, doingzomb);
981 			lwkt_rele(td);
982 			if (error)
983 				goto post_threads;
984 		}
985 	}
986 post_threads:
987 	lwkt_reltoken(&proc_token);
988 	return (error);
989 }
990 
991 /*
992  * This sysctl allows a process to retrieve the argument list or process
993  * title for another process without groping around in the address space
994  * of the other process.  It also allow a process to set its own "process
995  * title to a string of its own choice.
996  *
997  * No requirements.
998  */
999 static int
1000 sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
1001 {
1002 	int *name = (int*) arg1;
1003 	u_int namelen = arg2;
1004 	struct proc *p;
1005 	struct pargs *opa;
1006 	struct pargs *pa;
1007 	int error = 0;
1008 	struct ucred *cr1 = curproc->p_ucred;
1009 
1010 	if (namelen != 1)
1011 		return (EINVAL);
1012 
1013 	p = pfindn((pid_t)name[0]);
1014 	if (p == NULL)
1015 		goto done2;
1016 	lwkt_gettoken(&p->p_token);
1017 	PHOLD(p);
1018 
1019 	if ((!ps_argsopen) && p_trespass(cr1, p->p_ucred))
1020 		goto done;
1021 
1022 	if (req->newptr && curproc != p) {
1023 		error = EPERM;
1024 		goto done;
1025 	}
1026 	if (req->oldptr && p->p_args != NULL) {
1027 		error = SYSCTL_OUT(req, p->p_args->ar_args,
1028 				   p->p_args->ar_length);
1029 	}
1030 	if (req->newptr == NULL)
1031 		goto done;
1032 
1033 	if (req->newlen + sizeof(struct pargs) > ps_arg_cache_limit) {
1034 		goto done;
1035 	}
1036 
1037 	pa = kmalloc(sizeof(struct pargs) + req->newlen, M_PARGS, M_WAITOK);
1038 	refcount_init(&pa->ar_ref, 1);
1039 	pa->ar_length = req->newlen;
1040 	error = SYSCTL_IN(req, pa->ar_args, req->newlen);
1041 	if (error) {
1042 		kfree(pa, M_PARGS);
1043 		goto done;
1044 	}
1045 
1046 	opa = p->p_args;
1047 	p->p_args = pa;
1048 
1049 	KKASSERT(opa->ar_ref > 0);
1050 	if (refcount_release(&opa->ar_ref)) {
1051 		kfree(opa, M_PARGS);
1052 	}
1053 done:
1054 	PRELE(p);
1055 	lwkt_reltoken(&p->p_token);
1056 done2:
1057 	return (error);
1058 }
1059 
1060 static int
1061 sysctl_kern_proc_cwd(SYSCTL_HANDLER_ARGS)
1062 {
1063 	int *name = (int*) arg1;
1064 	u_int namelen = arg2;
1065 	struct proc *p;
1066 	int error = 0;
1067 	char *fullpath, *freepath;
1068 	struct ucred *cr1 = curproc->p_ucred;
1069 
1070 	if (namelen != 1)
1071 		return (EINVAL);
1072 
1073 	lwkt_gettoken(&proc_token);
1074 	p = pfindn((pid_t)name[0]);
1075 	if (p == NULL)
1076 		goto done;
1077 
1078 	/*
1079 	 * If we are not allowed to see other args, we certainly shouldn't
1080 	 * get the cwd either. Also check the usual trespassing.
1081 	 */
1082 	if ((!ps_argsopen) && p_trespass(cr1, p->p_ucred))
1083 		goto done;
1084 
1085 	PHOLD(p);
1086 	if (req->oldptr && p->p_fd != NULL) {
1087 		error = cache_fullpath(p, &p->p_fd->fd_ncdir,
1088 		    &fullpath, &freepath, 0);
1089 		if (error)
1090 			goto done;
1091 		error = SYSCTL_OUT(req, fullpath, strlen(fullpath) + 1);
1092 		kfree(freepath, M_TEMP);
1093 	}
1094 
1095 	PRELE(p);
1096 
1097 done:
1098 	lwkt_reltoken(&proc_token);
1099 	return (error);
1100 }
1101 
1102 SYSCTL_NODE(_kern, KERN_PROC, proc, CTLFLAG_RD,  0, "Process table");
1103 
1104 SYSCTL_PROC(_kern_proc, KERN_PROC_ALL, all, CTLFLAG_RD|CTLTYPE_STRUCT,
1105 	0, 0, sysctl_kern_proc, "S,proc", "Return entire process table");
1106 
1107 SYSCTL_NODE(_kern_proc, KERN_PROC_PGRP, pgrp, CTLFLAG_RD,
1108 	sysctl_kern_proc, "Process table");
1109 
1110 SYSCTL_NODE(_kern_proc, KERN_PROC_TTY, tty, CTLFLAG_RD,
1111 	sysctl_kern_proc, "Process table");
1112 
1113 SYSCTL_NODE(_kern_proc, KERN_PROC_UID, uid, CTLFLAG_RD,
1114 	sysctl_kern_proc, "Process table");
1115 
1116 SYSCTL_NODE(_kern_proc, KERN_PROC_RUID, ruid, CTLFLAG_RD,
1117 	sysctl_kern_proc, "Process table");
1118 
1119 SYSCTL_NODE(_kern_proc, KERN_PROC_PID, pid, CTLFLAG_RD,
1120 	sysctl_kern_proc, "Process table");
1121 
1122 SYSCTL_NODE(_kern_proc, (KERN_PROC_ALL | KERN_PROC_FLAG_LWP), all_lwp, CTLFLAG_RD,
1123 	sysctl_kern_proc, "Process table");
1124 
1125 SYSCTL_NODE(_kern_proc, (KERN_PROC_PGRP | KERN_PROC_FLAG_LWP), pgrp_lwp, CTLFLAG_RD,
1126 	sysctl_kern_proc, "Process table");
1127 
1128 SYSCTL_NODE(_kern_proc, (KERN_PROC_TTY | KERN_PROC_FLAG_LWP), tty_lwp, CTLFLAG_RD,
1129 	sysctl_kern_proc, "Process table");
1130 
1131 SYSCTL_NODE(_kern_proc, (KERN_PROC_UID | KERN_PROC_FLAG_LWP), uid_lwp, CTLFLAG_RD,
1132 	sysctl_kern_proc, "Process table");
1133 
1134 SYSCTL_NODE(_kern_proc, (KERN_PROC_RUID | KERN_PROC_FLAG_LWP), ruid_lwp, CTLFLAG_RD,
1135 	sysctl_kern_proc, "Process table");
1136 
1137 SYSCTL_NODE(_kern_proc, (KERN_PROC_PID | KERN_PROC_FLAG_LWP), pid_lwp, CTLFLAG_RD,
1138 	sysctl_kern_proc, "Process table");
1139 
1140 SYSCTL_NODE(_kern_proc, KERN_PROC_ARGS, args, CTLFLAG_RW | CTLFLAG_ANYBODY,
1141 	sysctl_kern_proc_args, "Process argument list");
1142 
1143 SYSCTL_NODE(_kern_proc, KERN_PROC_CWD, cwd, CTLFLAG_RD | CTLFLAG_ANYBODY,
1144 	sysctl_kern_proc_cwd, "Process argument list");
1145